Automatic Supervision in Milling

Abstract

The problems arising in milling which need automatic detection and control may be briefly listed as follows:

• 1. Sudden force overload, especially that arising from rapid traverse approach and entry of tool into the workpiece — this may be a component of constant force adaptive control.

• 2. Torque overload of the spindle drive causing spindle stall and a catastrophic build-up of cutting load — this may cause cutter breakage and/or spindle damage.

• 3. Milling cutter tooth chipping and breakage, which can occur for several reasons. Although not usually associated with other damage, this can nevertheless develop if the fault is not quickly detected and corrected.

• 4. Tool wear develops gradually and should be detectable before it reaches a critical value.

• 5. Chatter vibrations may cause damage to the tool edge and affect bearing life during roughing operations. They are liable to spoil the quality of machined surfaces during finishing passes, by generating deep chatter marks.

• 6. Severe resonant forced vibrations may develop in fine-finish end milling cuts on thin-walled parts, leading to bad surface finish and chipping of the cutting edge.